Hearing repair
Hair cells are naturally fragile. They must be delicate so they can sense sound, but they must also withstand the continuous mechanical stress inherent in their jobs.
Prolonged exposure to loud noise harms hair cells in a variety of ways, and one of those is by damaging the cores of the “hairs” themselves. These hair-like structures are known as stereocilia, and Shin’s new research shows a process they use to repair themselves.
The hair cells deploy a protein called XIRP2, which can sense damage to the cores that are made of a substance called actin. Shin and his team found that XIRP2 first senses damage, then migrates to the damage site and repairs the cores by filling in new actin.
This process is also relevant to the broader study of cell biology, Shin said.
The pioneering work netted Shin and his colleagues more than $2.3 million from the National Institutes of Health (grant R01DC021176) to fund additional research into how the cores are repaired. By understanding this, scientists will be better positioned to develop new ways to battle hearing loss – even loss due to aging, the researchers say.
“Age-related hearing loss affects at least a third of all older adults,” Shin said. “Understanding and harnessing internal mechanisms by which hair cells counteract wear and tear will be crucial in identifying ways to prevent age-related hearing loss. Furthermore, this knowledge holds potential implications for associated conditions such as Alzheimer's disease and other dementia conditions.”
Reference: Wagner EL, Im JS, Sala S, et al. Repair of noise-induced damage to stereocilia F-actin cores is facilitated by XIRP2 and its novel mechanosensor domain. King AJ, Alushin GM, eds. eLife. 2023;12:e72681. doi: 10.7554/eLife.72681
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